Several families of potentially melanophilic radiopharmaceuticals (based on quinolines, psoralens, and melatonin) have been proposed for synthesis, in vitro melanin binding studies, and tumor uptake measurements in animal melanoma models. Methods for isotopic incorporation will utilize either radioiodine or other suitable chelate-bound metal ion gamma emitters such as 99mTc. Chemical synthetic methods are being developed to complex reduced cationic Tc99m and produce complexes of low or neutral charge. Relative tumor/tissue distributions will be performed in hamsters bearing the Fortner melanoma by flank transplant. Time-dose distribution curves will permit evaluation of the optimum time post-administration for imaging.